1. Field of the Invention
The present invention relates to an insertion apparatus into which a curved-shape detection sensor is incorporated.
2. Description of the Related Art
It is known to incorporate a curved-shape detection sensor into an insertion apparatus (e.g. an endoscope) including an elongated insert section to be inserted into an insertion target and detect a curved shape (a curved angle and a curved direction) thereof.
For example, Jpn. Pat. Appln. KOKAI Publication No. 2003-52612 discloses an endoscope into which a curved-shape detection sensor is incorporated, wherein the curved-shape detection sensor includes a plurality of sensing parts for detecting a curved shape. The curved-shape detection sensor includes optical fibers including a core onto which light absorbers are formed only in a predetermined direction at portions from which a cladding is exposed. The curved-shape detection sensor detects a curved shape of the endoscope on the basis of the fact that the amount of light guided through the optical fibers varies with the curved angle and curved direction of the optical fibers. The curved direction is determined by means of a sensing part according to a light absorber which is formed in a predetermined direction. The optical fibers are not fixed to the proximal end of the endoscope and extend to cause a small wave such that they cannot be easily broken even though curvature appears repeatedly.